...Carol C...here is another quote from your link (2:53):

"The African non-Muslim citizens who populate the south have been at war with the central government, dominated by an Arabized Muslim elite, since independence in 1956. State power remains in the hands of this elite, which dominates the officer corps of the army, security agencies, and other implements of power—although poverty-stricken Africans from the Nuba Mountains, west and south of Sudan make up the bulk of the soldier class."

Is there a reason you chose 1983 as a starting date for the hostilities?

Clearly the big change is the money provided by selling the oil, not the oil itself. The Muslim elite now have enough money to buy arms and do a more effective job of genocide.